Interchangeable, power driven hammer head



April 7, 1959 A. H. MlDKlFF ET AL. 7 2,

INTERCHANGEABLE, POWER DRIVEN HAMMER HEAD Filed Marbh 2:, 1956 2 Sheets-Sheet 1 AT TO R. N EYS 2 Sheets-Sheet 2 A. H. MIDKIFF ET AL INTERCHANGEABLE, POWER DRIVEN HAMMER HEAD April 7, 1959 Filed March 23, 1956 INVENTOR. W\L.LIAM DAMRON ABRAHAM H. MIDKIFF A-r'roczNEvs' United States Patent INTERCHANGEABLE, POWER DRIVEN HAMNIER HEAD Abraham H. Midkilf, Crown, and William F. Damron, Logan, W. Va.

Application March 23, 1956, Serial No. 573,451

1 Claim. (Cl. 12533) cation of a piston in a cylinder or housing, such as air hammers, etc.

Heretofore, hammers powered by compressed air, fluid pressure, mechanical linkages, etc. have been devised, but considerable limitations have been placed on their use. For example, such hammers in many instances cannot be used in close spaces, a hammering action cannot be exerted around the corners of the work, and a change in direction in the applied, hammering forces has in many instances not been possible due to the permanent association of the hammer head with the means for actuating the same.

It may be stated as the broad, overall purpose of the invention, accordingly, that we aim to provide a hammer head which may be detachably assembled with a conventional means, whether mechanical, air powered, or otherwise driven for imparting reciprocating motion to the head, our hammer head being so designed that a selected hammer head can be associated with a single power supply means in a manner to apply a hammering force in any of a plurality of directions, to permit a worker to drill, batter, pound, bend, straighten, or otherwise act upon any of various metals, or other hard substances. The invention, further, is adapted for drilling, battering, or otherwise acting upon rock, cement, slate, and the like, in any direction and in close openings where the tool can be inserted endwise. Due to the detachable nature of the hammer heads devised by us, and due to the various directions of force provided by the several interchangeable heads, one can, for example, apply a hammering force at right angles to the line of force produced by the reciprocating piston of the holder, at 45 degrees to said line of force, and in a reverse direction to said line of force, along lines paralleling the same.

To this end, the present invention, summarized briefly, includes a hollow, compactly formed housing detachably assembled with the conventional tool that supplies the power, with the hollow casing including a pivoted hammer element acted upon at one side by the reciprocating piston of the tool, with the other side of the hammer element bearing against a reciprocating plunger having on its outer end a work-engaging head portion. The hammer element pivoted in the casing is so designed as to change the direction in which the hammering force is exerted, and in different embodiments of the invention, the plunger is in one instance extended perpendicularly to the driving piston, in another form at an angle of 45 degrees to the axis of the driving piston, and in another form in parallel relation to said driving piston but disposed to reverse the direction in which the hammering action would ordinarily be exerted by the piston.

It is further proposed to provide a device of the type referred to the principles of which can be applied for changing the direction of the hammering force in even other ways, so that said force can be exerted at any angle to the driving piston, separate and distinct from the 45 and degree angles mentioned. Still further, the invention is so designed as to permit, if desired, a plurality of plungers to be mounted in a single casing, said plungers extending at diflerent angles to the single driving piston that projects into the casing and being adapted to be selectively employed for accomplishing particular tasks.

Other objects will appear from the following description, the claim appended thereto, and from the annexed drawing, in which like reference characters designate like parts throughout the several views, and wherein:

Figure 1 is a perspective view showing a detachable hammer head formed according to the present inven tion, a power tool on which the head is mounted being shown fragmentarily;

Figure 2 is an enlarged longitudinal sectional view on lien 2-2 of Figure 1;

Figure 3 is a longitudinal sectional view on line 3-3 of Figure 2;

Figure 4 is a transverse sectional view on line 4--4 of Figure 2;

Figure 5 is an exploded perspective view of the detachable hammer head;

Figure 6 is a fragmentary longitudinal sectional view,- similar to Figure 2, on a reduced scale, showing a modified form in which the hammering action is exerted at 45 degrees to the axis of the tool body; and

Figure 7 is a view similar to Figure 6 showing a second modification in which the hammering force is exerted parallel to the tool body, but in a reverse direction.

Referring to the drawings in detail, in the form of the invention shown in Figures 1-5, there is designated at 10 an elongated, cylindrical body of a conventional power hammer. In this connection, a detachable hammer head can be mounted on any of various tools of this type, it

often impossible or at least is extremely diflicult, in closeareas in which full freedom of positioning of the elongated tool body is not possible.

In any event, the body 10 of the tool includes at one end a reduced, axial extension 12 having external threads thereon. Formed in the head end of the tool is an axial bore 14, opening at its inner end into the piston chamber 16 of the tool body, within which reciprocates a piston 18 having at one end a reduced axial extension 20. In the illustrated example, the piston 18 is reciprocated by compressed air, flowing through channels 22, 24 that open into a chamber 16. However, various other means for reciprocating the piston can be employed, and the invention is not limited to use with a particular tool illustrated.

The detachable hammer head constituting the present invention has been generally designated at 25 in Figures 1-5 and includes at one end a sleeve 26 having a threaded counterbore 28 at its outer end receiving the extension 12, the counterbore merging into a smaller diameter bore 30 opening upon the opposite end of the sleeve and receiving the bushing 32.

The sleeve is integrally formed with a hollow housing 34, having an opening extending along the top and outer;

"Reciprocating in "the bore 14 and projecting at one end into the housing is an elongated, 'floating piston member 40 having at its projecting end a head 42. Piston 40 at its other end extends adjacent the axial extension 20, so that on driving of the floating piston 18 to the right in Figure 2, said floating piston will strike the piston member 40 and shift the same axially of the body with great force and velocity to the right in Figure 2.

The head 42 bears against a hammer element 4-4 which in the form of Figures 1-5 has a tapering body merging at its smaller end into a portion 46 having an .opening extending perpendicularly to the axis of the piston member 40, and receiving a bolt 48 (Figures 2 and 3). Bolt 48 at one end is threaded in an opening formed in one side wall of the housing, the other end of the bolt engaging in an opening formed in the opposite side wall.

The hammer element 44, is thus rockably mounted upon the bolt 48, and at its other side, bears against an enlargement 50 formed upon the inner end of a straight plunger 52 reciprocating in an externally threaded bushing 54 that .is threadedly engaged in an opening formed in the wall of the housing 34.

A compression, coil spring is interposed between the bushing 54 and the enlargement 50, and normally tends to retract the plunger 52 within the housing. Plunger 52, at its outer end, has a rounded head portion 58 adapted to be directed against the work for the purpose oftpounding, battering, or otherwise acting upon the same.

The spring serves the purpose of retracting the plunger after each pressure stroke, and in shifting the plunger upwardly in Figure 2 following direction of the plunger against the work, it also discharges the function of pivoting hammer elements 44 counterclockwise in Figure 2, which pivotal movement in turn shifts floating piston 40 to the left in Figure 2. This in turn shifts the first floating piston 18 to the left in Figure 2, to a retracted position in which the piston 18 is illustrated in Figure 2. The channels 22 and 24, in this connection, are exhaust channels. Thus, when piston 18 is in its retracted position shown in Figure 2, compressed air is directed against the back wall of the piston, said compressed air being admitted to the back end, not shown, of the piston chamber and thus driving the piston 18 forwardly within the piston chamber.

.As the piston 18 is driven forwardly in its pressure stroke, channel 24 serves as an exhaust passage permitting air to be exhausted from the piston chamber forwardly of the piston. Channel 24 further serves to permit air to enter the forward portion of the piston chamber at such times as the piston 18 is being shifted through its return stroke, toward the left in Figure 2. Channel 24 may thus be communicated with atmosphere at'all times and serves to prevent a vacuum from being formed in the piston chamber in advance of the first floating piston, serving also to prevent compression of air within the forward portion of the piston chamber in a manner that would prevent the floating piston 18 from moving through its pressure stroke.

Meanwhile, channel 22 is exposed at the completion of the pressure stroke, by reason of the fact that the body of the piston 18 is of a length equal to the distance between the outlet of channel 22 and the front end wall of the piston chamber. Therefore, at the completion of the pressure stroke, the piston chamber, rearwardly of the piston 18, is communicated with atmosphere through channel 22, so as to immediately cause a cessation of pressure against the back end of the floating piston 18, whereby to permit the piston 18 to be moved through its'return stroke as the spring 56 expands.

It willbenoted that'the particular shape of the hammer element is such as'to change the direction in which force is exerted 'on reciprocation of the piston member 40. In other words, in theform of Figures 1-5 the plunger 52 has its axis normal to the axis of the piston member 40. Thepiston'member bears against one face of the hammer element 44, with the hammer element thus being shifted clockwise in Figure 2 by movement of the piston member 40 to the right in Figure 2. Since the opposite face of the hammer element is angular to the face thereof engaged by the piston member 40, it may bear against the enlargement 50, and thus, on clockwise swinging of the hammer element, it acts to extend in the plunger 52 against the restraint of the spring 56. At the end of the power stroke, spring 56 is free to expand, and retract the plunger 52, the plunger in turn shifting the hammer element 44 counterclockwise in Figure 2 and the hammer element 44 thus, in turn, shifting the piston member 40 to the right in Figure 2 to retract the piston member within body 10, awaiting the next power stroke of the floating piston 18.

In Figure 6 there is shown a modified construction wherein the hammer action is exerted along a line disposed at an angle 45 degrees to the axis of the piston member 40. In this form of the invention, the housing 34a has a sleeve 26a detachably assembled with axial extension 12. The housing is closed by an arcuate closure plate 46a, and rockably mounted in the housing is a hammer element 44a of tapered formation, one side edge of which is engaged by the piston member 40 and the other side of which engages the enlargement 50 of the plunger 52. The plunger 52, in this instance, is not perpendicular to the length of the piston member, but rather is at an angle oblique to the length of the piston member. Thus the hammering action is exerted in a direction different from that in which it is exerted in the first form of the invention. Apart from this,howev.er, the basic structural and functional characteristics of the invention are unchanged.

In Figure 7, there is shown a second modified form, wherein the head 34b is of approximately semicircular formation, having a sleeve 26b attached to the power tool. In this form the hammer element 44b is of approximately semicircular configuration, and has a straight edge extending diametrically of the pivot volt 48b on which the hammer element is rockably mounted. At one side of the pivot axis of the hammer element, the straight edge of the hammer element is engaged by the piston member, while at the opposite side, said straight edge engages the enlargement 50 of the plunger 52. The plunger in this instance is extended in parallel relation to the piston member, but exerts its hammering action backwardly, that is, toward the user.

It is believed that various other modifications may be readily designed, following the principles set forth hereinabove. In other words, one might, for example, desire to have the plunger operate along a line disposed at an angle or other than 45 or degrees to the line of force of the piston member, and the number of angles along which the hammering action could be exerted are, of course, so many as to make individual illustration of the various other modifications inappropriate.

It is mainly important, in this connection, that the hammer head constitutes a detachable, interchangeable device connectable to an otherwise conventional power tool, for the purpose of permitting a hammering action to be exerted along some line other than axially of the tool body.

Because of this characteristic of the invention, too, a selected, detachable hammerhead can be secured to a tool body for 'the purpose of accomplishing a particular task the working conditions of which are dictated by the relatively close area in which the hammering action must be exerted, etc. One might, for example, desire to exert a hammering action "along a predetermined path, with the tool body extending at an angle to said path,-within a close "space, and this is possible by selection of a suitable hammer head and its attachment thereof to the tool body. Then again, a completely reversed hammering action may be desired, along a path paralleling the tool body as shown in Figure 7, and it will be seen that many other conditions can be readily met by the device constituting our invention.

The particular size of the detachable hammer head will be selected according to the type of work to be done as well as to the size of the electric, air compressed, water, oil or gas hammer that serves as a support and power supply means for the detachable head.

The uses to which the hammer head can be put are, of course, many, and the device can readily be used for riveting, drilling, crimping thin metals, straightening or bending fenders and body parts of automobiles, tamping, crushing, etc. Our invention is intended to encompass any use to which the structure which we have devised can be adapted, within the scope of the appended claims.

It may be desirable to provide a socket base, not shown, detachably connectable to the housings of the various interchangeable heads illustrated and described herein. Such a base might be particularly desirable when the device is used in tamping railroad ties, crushing rock, etc. The socket base would rest directly upon the ground or other support surface, supporting the housing thereabove in position to permit the plunger to exert its hammering action. Under such circumstances the user may stand upright while using the device to work with more efficiency, ease, and uniformity of operation, with the device resting and sliding upon the ground or other support surface. The socket base would merely be a block-like formation, adapted to fit against the housing, and detachably connected to the housing by means of leather or metal straps or clamps extending from the base about the housing. In some instances, in fact, the housing itself may be thickened on one or more walls to provide a base that permits the housing to rest upon the ground.

Still further, one might desire to embody two plungers 52 in the same housing, both plungers extending at an angle to the piston member, with the plungers being at different angles to one another. In such an instance, the removal of one plunger will permit the hammer element to swing fully around into engagement with the other plunger, whereas insertion of said one plunger will dispose the same in the path of swinging movement of the hammer element so that it will receive the force of the hammer element, rather than the other plunger. Such an arrangement, rather, might embody the use of the plunger 52 of Figure 2, together with the plunger 52 of Figure 6. The plunger 52, when inserted through an opening of the closure plate 36 of Figure 2, would overlie the plunger of Figure 2, and would receive the force of the hammer element. On removal of the plunger of Figure 6, the hammer element could swing fully around to engage the plunger of Figure 2 instead.

It is believed clear that the invention is not necessarily confined to the specific use or uses thereof described above, since it may be utilized for any purpose to which it may be suited. Nor is the invention to be necessarily limited to the specific construction illustrated and described, since such construction is only intended to be illustrative of the principles of operation and the means presently devised to carry out said principles, it being considered that the invention comprehends any minor changes in construction that may be permitted within the scope of the appended claim.

What is claimed is:

The combination, in a power hammer, of a hollow, elongated body formed at one end with a reduced, externally threaded, axial extension, said body having an axial bore through said extension communicating with the interior of the body, said interior of the body constituting a piston chamber, the body having a side wall formed with longitudinal channels through which pressure fluid is adapted to flow, said channels opening upon said chamber at locations spaced longitudinally oi thg 13 chambers; a floating piston reciprocable within said piston chamber and adapted to be driven in opposite direc? tions responsive to the flow of air through said channels, said bore being of a diameter substantially smaller than that of the piston chamber, the piston being formed with a reduced axial extension of a diameter substantially equal to that of the bore, the piston having a body on one end of which said axial extension is formed, said body being of a diameter matching the diameter of the piston chamber for slidable engagement of said body of the piston with the wall of the piston chamber, the length of the body of the piston being equal to the distance between one end of the pistonchamber and the location at which one of said channels opens upon the piston chamber, said bore opening upon the piston chamber through said one end thereof, the location at which the other channel opens upon the piston chamber being disposed between said one end of the piston chamber and the location at which the first named channel opens upon the piston chamber; a second floating piston mounted within the bore for axial reciprocation and having an inner end projecting into the chamber and formed to a diameter matching that of the extension of the first piston, for striking of the second piston by the first piston on movement of the first piston through its pressure stroke, said first piston when moved through its pressure stroke being shifted toward said one end of the piston chamber with the piston body being disposed wholly between said one end of the piston chamber and said location at which the first named channel opens upon the piston chamber, whereby to bring into communication the piston chamber and said first named channel rearwardly of the piston body at the completion of the pressure stroke of the first piston, said piston body when at the completion of the pressure stroke extending across the location at which the second named channel opens upon the piston chamber so as to prevent communication between said second named channel and the piston chamber, the other end of the second piston projecting forwardly beyond the extension of the body and being formed with an enlarged head; a hollow housing have a sleeve-like, internally threaded inner end portion receiving the threaded extension of the body, said hollow housing being formed with a bore extending in a path dilferent from that in which the second piston is reciprocated; a hammer element pivotally mounted within the hollow housing for swinging movement about an axis normal to both of said paths, said hammer element having one side in engagement with the head of the second piston for swinging of the hammer element in one direction responsive to shifting of the second piston through its pressure stroke under the impact received thereby from the first piston; a plunger mounted in the bore of the housing for reciprocation in the second named path and having its opposite ends disposed one within the housing and the other exte-riorly of the housing, said one end of the plunger being in engagement with the other side of the hammer element; and a compression spring extending about said one end of the plunger and abutting at one end against the housing, said spring at its other end bearing against the plunger for biasing the plunger axially in one direction, the spring being under compression effective to maintain said one end of the plunger in engagement with the hammer element, said spring forming means for shifting the hammer element under pressure exerted thereagainst by the plunger in an opposite direction for imparting return, axial movement to the second and first pistons, said first piston when shifted in a return direction moving rearwardly within the piston chamber, away from said one end of the piston chamber, and being disposed in position across the second named channel while clearing the first named channel to provide communication between the first named channel and the piston chamber in advance of the piston body, the plunger at its other end having a rounded 'sponsive to reciprocation of the first named piston withgamma 27 head portion adapted to he directed against {the work 605,171 piece for .exerting a hammering action .therea-gainst re 1,652,493 2,626,598

in :the body.

170,129 Strohm Nov. 16, 1875 

